Composition About Environment Pollution

[Orville Marquez]

PM10and PM2.5 often derive from different emissions sources, and also have different chemical compositions. Emissions from combustion of gasoline, oil, diesel fuel or wood produce much of the PM2.5 pollution found in outdoor air, as well as a significant proportion of PM10. PM10 also includes dust from construction sites, landfills and agriculture, wildfires and brush/waste burning, industrial sources, wind-blown dust from open lands, pollen and fragments of bacteria.

PM may be either directly emitted from sources (primary particles) or formed in the atmosphere through chemical reactions of gases (secondary particles) such as sulfur dioxide (SO2), nitrogen oxides (NOX), and certain organic compounds. These organic compounds can be emitted by both natural sources, such as trees and vegetation, as well as from man-made (anthropogenic) sources, such as industrial processes and motor vehicle exhaust. The relative sizes of PM10 and PM2.5 particles are compared in the figure below.

CARB is concerned about air-borne particles because of their effects on the health of Californians and the environment. Both PM2.5 and PM10 can be inhaled, with some depositing throughout the airways, though the locations of particle deposition in the lung depend on particle size. PM2.5 is more likely to travel into and deposit on the surface of the deeper parts of the lung, while PM10 is more likely to deposit on the surfaces of the larger airways of the upper region of the lung. Particles deposited on the lung surface can induce tissue damage, and lung inflammation.

Short-term exposures to PM10 have been associated primarily with worsening of respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD), leading to hospitalization and emergency department visits.

Long-term (months to years) exposure to PM2.5 has been linked to premature death, particularly in people who have chronic heart or lung diseases, and reduced lung function growth in children. The effects of long-term exposure to PM10 are less clear, although several studies suggest a link between long-term PM10 exposure and respiratory mortality. The International Agency for Research on Cancer (IARC) published a review in 2015 that concluded that particulate matter in outdoor air pollution causes lung cancer.

Particulate matter has been shown in many scientific studies to reduce visibility, and also to adversely affect climate, ecosystems and materials. PM, primarily PM2.5, affects visibility by altering the way light is absorbed and scattered in the atmosphere. With reference to climate change, some constituents of the ambient PM mixture promote climate warming (e.g., black carbon), while others have a cooling influence (e.g., nitrate and sulfate), and so ambient PM has both climate warming and cooling properties. PM can adversely affect ecosystems, including plants, soil and water through deposition of PM and its subsequent uptake by plants or its deposition into water where it can affect water quality and clarity. The metal and organic compounds in PM have the greatest potential to alter plant growth and yield. PM deposition on surfaces leads to soiling of materials.

Ambient air quality standards define the maximum amount of pollutant that can be present in outdoor air without harming human health. In 2002, after an extensive review of the scientific literature, the Board adopted a new annual average standard for PM2.5, and retained the existing annual and 24-hour standard average standards for PM10. The national annual average PM2.5 standard was most recently revised in 2024 following an exhaustive review of new literature pointing to evidence for continued risk of premature mortality and other health effects at lower PM2.5 concentrations than the existing standard. The latest review resulted in retention of the existing 24-hour average PM2.5 and PM10 standards.

The Asthma and Allergy Foundation of America (AAFA), a not-for-profit organization founded in 1953, is the leading patient organization for people with asthma and allergies, and the oldest asthma and allergy patient group in the world.

More than 27 million people in the United States have asthma. The best way to manage asthma is to avoid triggers, take medications to prevent symptoms, and prepare to treat asthma episodes if they occur.

AAFA offers a variety of educational programs, resources and tools for patients, caregivers, and health professionals. AAFA launches educational awareness campaigns throughout the year. We teach the general public about asthma and allergic diseases.

Research is an important part of our pursuit of better health. Through research, we gain better understanding of illnesses and diseases, new medicines, ways to improve quality of life and cures. The Asthma and Allergy Foundation of America (AAFA) conducts and promotes research for asthma and allergic diseases.

AAFA works to support public policies that will benefit people with asthma and allergies. Advocacy and public policy work are important for protecting the health and safety of those with asthma and allergies. We advocate for federal and state legislation as well as regulatory actions that will help you.

There are several ways you can support AAFA in its mission to provide education and support to patients and families living with asthma and allergies. You can make a donation, fundraise for AAFA, take action in May for Asthma and Allergy Awareness Month, and join a community to get the help and support you need.

Nitrogen dioxide (NO2) comes from burning fuels. It also forms from emissions from cars, trucks, other vehicles, and power plants. It is part of smog (haze). Breathing in NO2 can cause someone to develop asthma. It can worsen lung disease, especially asthma.3

Sulfur dioxide (SO2) comes from burning fossil fuels, transportation, volcanoes, and industrial processes. It can be found in smog or haze. SO2 can harm plants (including trees). It can harm your lungs and lead to health problems.4

Methane (CH4) is another gas that is part of air pollution. It mostly comes from animal agriculture and in subarctic regions where it is released from melting permafrost. Fossil fuels (oil, gas, coal) and waste (food, landfills, wastewater) also add methane to the air. Methane is 30 times more potent at trapping heat than carbon dioxide (CO2) as a major greenhouse gas that is worsening the climate crisis. Methane can turn into ground-level ozone, which is harmful to human health.5

When the AQI is 101 or higher, it is unhealthy for people with asthma. You may have to change your activities and medicines. If you have asthma, your symptoms can worsen even when AQI levels are moderate (AQI 51-100).

When air pollution is high, people with asthma should limit their time outdoors, especially from 11 a.m. to 8 p.m. Stay in a well-ventilated, preferably air-conditioned, building. Most of all, do not exercise or work hard outdoors when the AQI is at unhealthy levels.

Home is where you cook, eat, sleep, bathe, groom, relax, and play with pets. Indoor air pollution can pose a health risk. Your home may have small particles in the air or damaging gases such as carbon monoxide.

Yes, but your concern should be appropriate to the type of environment you work in. If you work outdoors, or if you work with certain chemicals, sprayed substances, powders or known carcinogens or allergens, your risk may be high. The Occupational Health and Safety Administration (OSHA) requires your employer to reduce your risk.

Even if you work in what seems to be a chemical-free environment, you may have exposure to indoor or outdoor air pollution. No matter how old the building is, there may be hidden indoor air pollution. Buildings may have mold spores or cockroaches. These are both powerful allergens. Dust mites are in most indoor areas. New carpet may release toxic fumes. Poorly filtered air systems may spread allergens and irritants. If they are damp, they may actually breed mold spores. If your employer allows tobacco smoking in the building, smoke may pollute the air you breathe.

Over the past 15 years, there have been moderate advances in U.S. public policy, health care and research, but racial gaps in asthma outcomes have not changed. Minority groups continue to bear disproportionate hardship in managing asthma.

A new study published in Atmospheric Environment by researchers at the University of North Carolina at Chapel Hill analyzed space and time trends for fine particulate matter (PM2.5) in the continental United States to track the progress of regulatory actions by federal, state and local authorities aimed at curbing air pollution. The team found that while the annual average concentration for PM2.5 had been significantly reduced, its chemical composition had changed during the study period of 2006 to 2020. Their analysis suggests targeted strategies to reduce specific pollutants for different regions of the U.S. may be more effective in further reducing total air pollution and PM2.5 -related adverse health effects. PM2.5, an airborne pollutant, is a mix of multiple chemical species and includes fine particles less than 2.5 microns in size. PM2.5 has been linked to many adverse human health effects including premature death. It also can reduce visibility by creating haze in the air.

The biggest air quality improvements during this 15-year period that was analyzed were observed in areas with the worst baseline air quality. The Ohio Valley and southeastern states, for example, had the biggest improvements due to regulations on emissions sources such as coal-burning power plants and industry. Sulfur dioxide emissions, a byproduct of fossil fuel combustion, decreased 91.5% from power plants during the study period. Most of the sulfur dioxide emissions in the study came from the Ohio Valley and the southeastern U.S. A spike in poor air quality along the West Coast in 2020 was likely due to widespread forest fires.

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