Which of the following represents primary air pollutants?

Primary air pollutants are substances that are emitted directly into the atmosphere from source activities. They include a variety of compounds that can have harmful effects on health and the environment. Among the choices presented, hydrocarbons and particulates are identified as primary air pollutants because they are released directly from sources such as vehicle exhaust, industrial emissions, and combustion processes.

Hydrocarbons, which include volatile organic compounds (VOCs), are typically emitted from burning fossil fuels and can contribute to the formation of ground-level ozone when they react with sunlight. Particulates, which include dust, soot, and smoke, are released from sources like construction activities, industrial processes, and natural events such as wildfires. These substances can adversely affect air quality and human health, leading to respiratory issues and other environmental impacts.

In contrast, ozone, although it is harmful, is considered a secondary pollutant because it is formed in the atmosphere through chemical reactions involving primary pollutants, and carbon dioxide, while a significant greenhouse gas, is also not regarded as a primary pollutant in this context. Fertilizers and pesticides are not classified as air pollutants but rather as agricultural chemicals, and chlorofluorocarbons (CFCs) are synthetic compounds that primarily affect the ozone layer and