Union of Concerned Scientists

MAY 21, 2025

Between 1990 and 2020, national concentrations of ozone were reduced by 25 percent, but this progress is eroding. Ozone is produced from precursors in the presence of ultraviolet radiation from sunlight, and global warming creates conditions favorable to ozone formation by accelerating chemical reactions.

Ozone 227

Ozone Ground-Level Ozone Air Pollution Clean Air Act 227

Legal Planet

NOVEMBER 8, 2021

It replaced an earlier, more dangerous, product called “town gas” or “coal gas,” which consisted mainly of hydrogen and carbon monoxide and was produced by heating coal in. For example, methane stayed roughly flat for about a decade from the late 1990s, but has increased rapidly since then – by nearly 16 ppb in 2020 over 2019.

Atmosphere 148

Atmosphere Radiation Natural Gas Greenhouse 148

Union of Concerned Scientists

SEPTEMBER 26, 2024

Fossil fuel combustion produces carbon dioxide (CO2), the most abundant global warming pollutant, but also produces local pollutants such as fine particulate matter (PM2.5), nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs). Bermix Studio/Unsplash PM2.5: A subset of these particles, called PM2.5,

Ground-Level Ozone 259

Ground-Level Ozone Fossil Fuels Ozone Air Pollution 259

HumanNature

MARCH 31, 2021

Guest Post By Erin Boedicker , 2020-2021 Sustainability Leadership Fellow and Ph.D. Black carbon is one type of airborne particulate matter (PM), which is a title for all the microscopic solid and liquid particles suspended in our air. Whenever there are combustion processes, of which there are many in our industrial society (e.g.,

Atmosphere 52

Atmosphere 2020 Carbon Emissions 2012 52