Across the country, pollution has drastically declined since the 1970s because of the Clean Air Act’s expansion, but the health impact of dirty air is still widely felt. According to the World Health Organization, air pollution is associated with 7 million premature deaths annually, with nearly 200,000 of those happening in the United States.

The federal government is expected to reconfigure its air pollution standards every five years to limit these impacts based on industry trends and new scientific data. However, the improvement of each ambient air pollution standard is far behind schedule. Given the Biden administration’s elevation of environmental issues, there is an expectation that many of these standards will be updated soon to address poor health outcomes disproportionately found in communities of color.

As the administration engages with the fallout of decades of environmental injustices, Worldacad is here to answer your questions about air pollution and its impact on your life. If you’re looking for information about environmental issues in your community that you don’t see below, reach out to our environmental reporter Adam Mahoney through this Google Form.

What are the biggest air pollutants?

The EPA lists six air pollutants as the most commonly emitted in America:

  • Carbon monoxide is an odorless gas that is released when something is burned.
  • Nitrogen oxides are a set of highly reactive gasses released from burning of fuel.
  • Lead is a naturally existing element found in the earth’s crust that is typically released in the air from industrial sites.
  • Ground-level ozone naturally occurs in the Earth’s upper atmosphere and at the ground level, but it is harmful in high concentrations.
  • Particulate matter is a mixture of liquid droplets and solid particles, such as dust, dirt, and smoke.
  • Sulfur oxides are chemicals that are released into the air from burning fossil fuels.

What are the major sources of air pollution?

  • Carbon monoxide: Power plants, metal manufacturing, electricity supply, and cars and trucks. It is also often emitted from machines that burn fossil fuels such as stoves, chimneys, and heaters.
  • Nitrogen oxides: Modes of transportation like cars and trucks, and power plants.
  • Lead: Lead smelters, waste incinerators, metals processing, and leaded aviation fuel.
  • Ground-level ozone: Cars, power plants, industrial boilers often used at power plants, refineries, and chemical plants that process plastic.
  • Particulate matter: Demolition and construction sites, power plants, cars, and wildfires.
  • Sulfur oxides: Power plants and other industrial facilities.

What are the health and environmental effects of air pollutants?

  • Carbon monoxide
    • Health: Carbon monoxide removes oxygen from the blood and deprives the heart, brain, and other vital organs of oxygen. It can cause confusion, dizziness, unconsciousness, and suffocation. The pollutant has also been linked to low birth rates and brain development delays.
    • Environment: In the atmosphere, carbon monoxide affects the way that greenhouse gasses react to one another, leading to increased sea and land temperatures and increased storm activity.
  • Nitrogen oxides
    • Health: Nitrogen oxides irritate airways, triggering wheezing, asthma attacks, and other respiratory diseases. It has been linked to higher incidences of lung cancer.
    • Environment: Interacting with water, oxygen, and other chemicals in the atmosphere, nitrogen oxides harm coastal ecosystems, water sources, and the prosperity of forests.
  • Lead
    • Health: Lead found in the air can infiltrate the body and spread through our blood and accumulate in our bones. It affects our decision-making abilities, kidney function, immune system, reproductive systems, and the heart. It has also been linked to learning disabilities in children.
    • Environment: Lead found in the air is known to trickle down into our soil and groundwater, as well as larger water systems. It is known to decrease soil fertility and kill insects and animals as it spreads throughout ecosystems.
  • Ground-level ozone
    • Health: Ozone pollution inflames and damages airways, aggravating lung diseases and increasing the frequency of asthma attacks. Children have the greatest risk from high levels of ozone pollution because their lungs are still developing.
    • Environment: Ozone pollution impacts water quality and slows the growth of plants, often killing numerous different types of U.S. tree species.
  • Particulate matter
    • Health: Particulate matter is so tiny that it can slip past our body’s defense system and infiltrate our bloodstream and lungs. It has been linked to increased asthma rates and lung and heart disease.
    • Environment: The pollutant is known to deplete nutrients in soil and water sources, damage large-scale crops, and create widespread haze, decreasing visibility.
  • Sulfur oxides
    • Health: Concentrations of sulfur oxides make it more difficult to breathe and cause irritation to the eyes, nose, and throat. It also increases the prevalence of asthma and heart disease.
    • Environment: Sulfur oxide pollution is connected to decreased plant and crop growth, in return decreasing biodiversity in ecosystems across the world.

How do these pollutants specifically harm Black communities?

  • Carbon monoxide: National studies have found that Black households consume the most natural gas, elevating the likelihood of carbon monoxide leaks and poisoning.
  • Nitrogen oxides: Level of exposure to nitrogen oxides is influenced by race. Most often emitted from transportation sources, Black communities are especially at risk because of their greater proximity to highways and major thoroughfares.
  • Lead: Lead pollution has been found in higher concentrations in Black communities, disproportionately impacting childhood development. It is often emitted into the air from demolitions in Black communities that have been left vacant and blighted from disinvestment. Studies have connected it to lower educational success and higher hospitalization rates for lead poisoning in Black children.
  • Ground-level ozone: Much like nitrogen and sulfur oxides, Black folks are most often exposed to ozone pollution from cars and power plants. Black people are 75% more likely than white people to live in proximity to polluting power plants.
  • Particulate matter: While Black, Latino, and Asian people all experience above-average exposure to PM 2.5, a 2021 study found that Black folks are exposed at a rate that is 21 percent higher than average. The racial disparities are found across the country regardless of income level and in rural or urban areas

Read more: The EPA Moves to Limit This Pollutant That Hurts Black People Disproportionately


What are air quality standards?

Air quality standards were introduced widely to the country after the Clean Air Act aAmendments of 1970. Their overarching goal is to protect human health, with a secondary goal to protect the environment.

An air quality standard defines “clean air” by determining the maximum amount of a pollutant that can exist in the air over a specific time period without harming public health. Air quality standards characterize pollution at the daily level as well as annually. Typically, higher amounts of pollution are allowed daily as long as the average amount of that pollutant is lower across the year. For example, the daily limit for particulate matter is three times higher than the annual limit.

What are the current U.S. air quality standards, and when were they last updated?

The Clean Air Act requires the EPA to review, and revise if necessary, each of the standards at five-year intervals to ensure that they are based on the most recent scientific findings. Each standard review is behind schedule.

How are standards selected?

The process for setting federal air standards takes about five years. It begins with an extensive scientific review that 1) assesses the successes and failures of the last air quality standard and 2) conducts modeling for the potential effects of a new standard.

The EPA uses three reviews for this process: the Integrated Science Assessment, Risk and Exposure Assessment, and a Policy Assessment. These three reviews are then released for public comment and public peer review by scientists and officials across the country. Following public comment, each document goes through two to three drafts before being finally approved by the EPA.

What happens when a community does not meet air quality standards?

The federal government can fine local governments and withhold federal funding if a state or county does not meet air quality standards. However, places that do not meet air standards are often put under government plans to lower emissions. Due to the nature of air pollution — which is often driven by multiple sources such as cars, industrial plants, and even entities like schools and universities — it can often take communities years and even decades to meet air quality standards.

How can I check my community’s air quality?

There are dozens of tools available to check your community’s air quality, maintained by numerous public and private institutions, including the federal government. Here are a couple:

AirNow and PurpleAir use the Air Quality Index, which measures air quality from 0 to 500. It consists of six categories, from “good” to “hazardous.” A score of 50 or below represents good air quality, while a score over 300 represents hazardous air quality that is unhealthy for anyone to breathe.

How can I learn more about air pollution’s impact on my community?

There are several places to learn about air pollution around your home. Tools like the EPA’s EJ Screening Tool and the White House’s Climate & Economic Justice Screening Tool allow you to enter your address, ZIP code, city, or county to receive information about your risks for climate change and pollution.

A simple Google search that combines your city or county plus the phrases “environmental justice” or “climate change” will also return several sources, such as community organizations focused on these issues and government or public research about your region.

Adam Mahoney is the climate and environment reporter at Worldacad. Twitter @AdamLMahoney