Air Quality

Emissions Events

Occasionally, Harris County’s facilities experience what is referred to as an emissions event. An emissions event is an upset event or unscheduled maintenance, startup, or shutdown activity resulting in unauthorized air contaminants emissions from one or more points at a facility. These unscheduled events may include smoking flares, releases from storage vessels or process areas, and fires. These events can result in large quantities of air contaminants being released and possibly impact nearby communities. PCS has assigned staff to specifically investigate emissions events and work with the facilities in an effort to reduce their occurrence and impact.

View the Texas Commission On Environmental Quality (TCEQ) Air Emission Event Report STEERS Database to search for emission events.

Pollution Control Services (PCS) Outdoor Air Program conducts activities that include complaint response and investigations, monitoring activities, emissions events investigations, programmatic inspections, and permit reviews. View the current air quality forecast.

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Complaint Response and Investigations

Responding to complaints and conducting investigations is one of PCS’ highest priorities. PCS has historically relied on citizen complaints and enforcement of the Nuisance Rule and Outdoor Burning Rule to address air pollution in Harris County. For more information, view our Field Services Page.

Programmatic Inspections

PCS also conducts inspections that focus specifically on certain types of facilities that have the potential to impact nearby communities. Harris County is in a nonattainment area of the EPA’s 8-hour National Ambient Air Quality Standard for ozone. Facilities such as paint booths, gas stations, and storage tank facilities are common sources of ozone forming pollutants that PCS investigates. In addition, PCS focuses on sources of particulate, or what may be more commonly known as smoke or dust.  PCS regularly inspects particulate sources such as rock crushers, concrete batch plants, and outdoor burning operations.

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Monitoring Activities

Ozone is extensively monitored in Harris County. In the early 2000s PCS contributed to the regional ozone monitoring network by installing 12 ozone monitors. These monitors were installed in strategic locations to provide a more comprehensive picture of overall air quality in Harris County, specifically in areas lacking ozone data. PCS dedicates staff to ensure these monitors collect quality data. To date, all 12 monitors are still in use, and the data collected can be viewed on the TCEQ’s monitoring website. For more information, view our Ozone Page.

PCS also utilizes multiple types of handheld monitoring equipment during certain activities, inspections, and special projects.


Harris County is a designated nonattainment area for the EPA’s 8-hour ozone standard. Harris County and other state and local agencies participate in maintaining a monitoring network to provide the public with current ozone data and advisories.

Ozone (O3) is a compound containing three oxygen atoms. Molecules of normal oxygen (O2) are composed of two oxygen atoms. Ozone can be found in the upper atmosphere and at ground level. It occurs naturally in the upper atmosphere, where it blocks harmful UV radiation. It forms at ground level when pollutants react to form photochemical smog. Ozone is highly reactive, and at high concentrations, it may corrode metals, degrade plastics, and cause respiratory irritation.


Ozone Formation

Ozone forms at ground level when nitrogen oxides (NOx) and volatile organic compounds (VOC) combine in sunlight. NOx is found in car exhaust and industrial emissions. VOC enters the atmosphere from industrial emissions, paints, solvents, evaporated gasoline, and natural sources. The ideal conditions for ozone formation are hot, clear days with calm winds. 

Stay Informed
Daily air quality forecasts, provided by the TCEQ can be found here.
A map with current ozone levels in Harris County can be viewed here.

What to do when Ozone levels are high

Ground level ozone can cause inflammation of the lungs. Some studies have also linked ozone exposure to increased heart attack and respiratory infection incidence. Sensitive individuals such as people with respiratory conditions, parents of young children, and the elderly should pay close attention to ozone warnings and avoid outdoor activity when ozone levels are high. Strenuous outdoor exercise should also be avoided when ozone levels are high.

You can help
You can assist in reducing ozone levels in Harris County. Maintain your vehicle to reduce emissions. Fill your gas tank and mow your lawn in the evening when ozone formation is low. Use public transportation where available. Conserve electricity to reduce emissions from power plants. It will take the cooperation of the public, industry, and regulatory agencies to restore our air quality in Harris County. Thank you for doing your part.


Permit Review

The Texas Commission on Environmental Quality is responsible for issuing air permits regulating facilities that emit air pollution. These permits can be for both major and minor stationary sources of air pollutants and specify emission limits and requirements for construction and operation. Permit conditions also specify the emission testing and monitoring requirements applicable to each source. For more information, view our Permits and Technical Services Page.

Hazards and Risks After A Fire

Fire and explosion accidents are of major concern to the owners and operators of many industries, Harris County residents, and Government agencies like PCS. Although incidents may be unpredictable, we can prepare before an event happens. Please review the following reports and fact sheets to learn the risks and how to prevent exposure to air pollution during an incident.

Fire Hazards For Chemicals Report
Potential Health Risks After Fires Report

Fact Sheets
Fire Hazards For Chemicals Fact Sheet
Potential Health Risks After Fires Fact Sheet

CAMP Dashboard

Need help navigating the CAMP Dashboard? Watch the overview video here!

CAMP History and Weather Data

Click Here to view the CAMP History and Weather Data.

CAMP Dashboard FAQs

What do the VOC numbers mean?

The VOC number on the CAMP dashboard is a reading of total Volatile Organic Compounds measured by a photoionization detector (PID) with a 10.6 eV lamp. The PID detects may different VOCs but cannot tell them apart. Because some VOCs cause the PID to have a stronger response than others, the readings produced by this sensor are intended to provide a qualitative indication of the presence of VOC. A year to date average for each site is provided to give context to the current day’s average displayed on the dashboard.

What are VOCs?

VOCs or Volatile Organic Compounds are chemicals that contain carbon and react in the atmosphere to form ozone.

Is there any way to identify the VOCs that the CAMP monitors detect?

The monitors are designed to trigger a sample canister when they detect high levels of VOC. The canisters can then be collected and taken to a lab for analysis. PCS is currently developing criteria for sample collection and is testing canister samples at 4 CAMP sites. Eventually, all the CAMP VOC monitoring sites will be equipped with these canisters.

Why are VOC readings higher at John Phelps and North Channel Library than at other sites?

The VOC monitors at John Phelps and North Channel Library are provided by a different manufacturer than at PCS’ other monitoring sites. The factory calibration of these two monitors produces higher baseline readings than our other sites. PCS will normalize the readings between the two different models of VOC monitor in an upcoming round of calibrations.

What is PM?

PM is the mixture of extremely small solid particles and liquid droplets suspended in the air (dust, dirt, soot, or smoke, ash, metals and allergens), and other various solid and liquid hazardous chemicals found in the atmosphere.

What is PM 1, 2.5, and 10?

Particulate Matter is classified according to size. PM2.5 are “Fine inhalable particles,” that are 2.5 microns in diameter and smaller. PM1 are “Ultra-fine inhalable particles,” that are 1 micron in diameter and smaller. PM10 are "Inhalable coarse particles," that are 10 microns in diameter and smaller. PM2.5 and PM1 are of greatest concern to human health. They can get deep into the lungs and enter the bloodstream where they may cause adverse health effects. Larger particles are of less concern as they tend to collect in the upper portion of the respiratory system.

How can I obtain cannister sample data?

PCS plans to post cannister sample results on the PCS website. Currently, canister sample data from the four canister sample test locations are available on request.

Why are there occasional changes in the data history?

PCS will periodically remove data that is not valid because it was collected during monitor maintenance or is the result of malfunction.

Air Quality and Ozone FAQs

How do I make a complaint or report a pollution violation?

If you live in the unincorporated area of Harris County or within the city limits of any city in Harris County, except Houston, you can call us at (713) 920-2831, 24 hours per day.

If you live within Houston City limits, call 311. Call (832) 393-5730 to report pollution within the City of Houston if you are calling from a non-Houston phone number. If you live outside Harris County, call the TCEQ at (713) 767-3500.

Your name will be kept confidential.

Can I burn my trash and leaves?

If you live in the unincorporated areas of Harris County you can burn trash and leaves produced at your residence if you do not have regular garbage service provided by a government agency. You should check your deed restrictions also. You cannot burn any material generated by a business. If you live inside the Houston City Limits contact the Bureau of Air Quality Control at (713) 640-4200 for information on burning. If you live inside the city limits of any other city, call your city health department or fire marshal.

You may not cause a nuisance to your neighbors under any circumstances.

Does Harris County issue any air permits?

Harris County does not issue any air permits. The state agency Texas Commission on Environmental Quality (TCEQ) is the permitting authority. Pollution Control Services coordinates with both the TCEQ Region 12 Office located in Houston (713) 767-3500 and the Central Office located in Austin (512) 239-1000 concerning activities that require and issuance of air permits.

Ozone, what is it, what causes it?

The EPA has designated Harris County as being in moderate nonattainment of its 8-hour ozone standard. Harris County participates with other state and local agencies in maintaining a monitoring network to provide the public with current ozone data and advisories.

Ozone (O3) is a compound containing three oxygen atoms. Molecules of normal oxygen (O2) are composed of two oxygen atoms. Ozone can be found in the upper atmosphere and at ground level. It occurs naturally in the upper atmosphere where it blocks harmful UV radiation. It forms at ground level when pollutants react to form photochemical smog. Ozone is highly reactive and at high concentrations it may corrode metals, degrade plastics, and cause respiratory irritation. For more information, view our Ozone Page.

Particulate matter, What is it? What causes it?

Particulate matter is the term for particles found in the air including dust, dirt, smoke, soot and liquid droplets. Particles can be suspended in the air for long periods of time. Some particles are large or dark enough to be seen as dust or smoke. Others are so small that they can be seen only with an electron microscope. Some particles are directly emitted into the air. They come from a variety of sources such as smoking vehicles, construction sites, tilled fields, unpaved roads, stone crushing, and open burning. Other particles are formed in the air from chemical reactions of gases in the presence of sunlight and water vapor. They result from emissions of sulfur dioxide, nitrogen oxides, ammonia, and volatile organic compounds-gases emitted by cars, power plants, industrial plants, gasoline dispensing facilities, painting operations, and natural sources. For more information follow this link.

Air toxics or hazardous air pollutants, what are they?

The Federal Clean Air Act regulates 187 chemicals that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects.

Listed hazardous air pollutants include benzene, which is widely used in the United States; it ranks in the top 20 chemicals for production volume. Some industries use benzene to make other chemicals that are used to make plastics, resins, and nylon and synthetic fibers. Benzene is also used to make some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Benzene is also a natural part of crude oil, gasoline, and cigarette smoke. For more information follow this link.

1,3-Butadiene is a chemical made from the processing of petroleum. Most of the 1,3-Butadiene manufactured is used in the production of synthetic rubber. It is also used in the production of plastics and acrylics. These synthetic materials are used to manufacture automotive tires and tire products, automotive hoses, belts, seals, and gaskets. It is also used as a chemical intermediate in the production of some fungicides, and in the manufacture of latex adhesives, nylon carpet backing, paper coatings, pipes, conduits, electrical components and luggage. Small levels of 1,3-Butadiene are found in gasoline. For more information follow this link.

Dioxin, asbestos, toluene, and metals such as cadmium, mercury and chromium compounds are also air toxics. For more information on HCPCS’ Environmental Toxins Control Program, including Air Toxics, please view our Environmental Toxins Control Program Web Page.