What are the effects of particulate matter?

• A. Increases photosynthesis
• B. Blocks sunlight and can have toxic or carcinogenic effects
• C. Improves cardiovascular health
• D. Decreases the greenhouse effect

Answer: (B)

Particulate matter are tiny particles suspended in the air that interact with light and human health. These particles scatter and absorb sunlight, which can block sunlight from reaching the ground and reduce visibility. At the same time, many particles carry toxic substances such as heavy metals and organic compounds; when inhaled, these can irritate the respiratory system and contribute to serious health risks, including cancer with certain types of particles. That combination—blocking sunlight and containing potentially toxic or carcinogenic components—is why this effect is best described by the selected idea.

The other notions don’t fit as well: particulate matter does not increase photosynthesis; in fact, by reducing light it can hinder it. It does not improve cardiovascular health; exposure to PM is linked to negative cardiovascular outcomes. Its influence on the greenhouse effect is complex and not simply a decrease, whereas the most consistent and direct effects are light blocking and toxicity.