Particulate matter and environmental impact
Particulate matter and environmental impact
Atmospheric particulate matter (PM) is a collection of microscopic solid and liquid particles suspended in the air. These particles can vary in size, composition, and origin, and are commonly classified based on their diameter:
– PM10 (particulate matter with a diameter ≤ 10 micrometers);
– PM2.5 (particulate matter with a diameter ≤ 2.5 micrometers);
– PM1 (ultrafine particulate matter ≤ 1 micrometer)
PM can be of natural origin (such as soil dust, pollen, volcanic ash, marine aerosols) or anthropogenic, resulting from human activities (such as vehicular traffic, industry, biomass combustion, home heating, intensive agriculture).
From a typological perspective, we can categorize three types of PM:
– Primary PM: This is the set of particles emitted directly into the atmosphere from various sources (sea salts, mineral or volcanic dust, direct emissions from traffic or industrial plants, etc.).
– Secondary particulate matter: Consists of particles that were not directly released into the air but were formed during gas-particle conversion processes (sulfates, nitrates, some organic compounds) that occurred in the atmosphere. They are primarily formed from nitrogen oxides (NOx) under the effect of solar radiation.
– Fine particulate matter: Particulate matter suspended in the atmosphere with a diameter < 2.5 μm (PM2.5).
Chemical composition –
The chemical composition of particulate matter may include: Heavy metals (lead, cadmium, arsenic) Sulfates, nitrates, ammonia Polycyclic aromatic hydrocarbons (PAHs) Volatile organic compounds (VOCs)
Negative impacts of particulate matter on biodiversity and agriculture –
Particulate matter is one of the most harmful air pollutants, not only for human health but also for the environment.
1. Impacts on biodiversity: Ecosystem contamination: Particulate matter, deposited on soil and surface water, can alter the chemical composition of the environment. Heavy metals and other toxic compounds accumulate in sediments and plants, entering the food chain and causing toxic effects on animals, insects, and microorganisms. Physiological stress in plants and animals: The presence of particulate matter on leaf surfaces reduces photosynthesis and alters transpiration. Some chemical compounds can also interfere with the development and reproduction of animal species, especially invertebrates and amphibians. Habitat alteration: The accumulation of particulate matter can change soil composition and alter vegetation, with cascading effects on natural habitats. The most sensitive or specialized species risk extinction, favoring more resistant ones and reducing biological diversity.
2. Impacts on agriculture: Direct damage to crops: Particulate matter settles on plant leaves, clogging stomata and reducing photosynthetic efficiency. This can lead to a decline in agricultural productivity, especially for crops such as vegetables, cereals, and fruits. Absorption of toxic substances: Some pollutants associated with particulate matter, such as heavy metals or volatile organic compounds, can be absorbed by plants through their roots or leaves. This compromises the food quality of agricultural products and poses health risks to consumers. Soil acidification: Particulate matter containing sulfur and nitrogen oxides can contribute to acid rain, which alters soil pH, compromises nutrient availability, and harms beneficial microorganisms. Impairment of pollinators: Pollutant particles can disrupt pollinating insects (such as bees and butterflies), altering their olfactory perception, navigation ability, and survival. This directly impacts the reproduction of cultivated and wild plants.