According to the Environmental Protection Agency (EPA), hazardous waste is generally classified into four main categories:

1. Characteristic Wastes: These exhibit at least one of four hazardous traits: ignitability (flammable, like gasoline), corrosivity (can rust or decompose materials, like car batteries), reactivity (unstable and can explode, like aerosol cans), or toxicity (harmful when ingested, like lead-based paint).

2. Listed Wastes: These are specific wastes from manufacturing and industrial processes that the EPA has officially designated as hazardous. They include byproducts from processes that use solvents, pesticides, and other chemicals.

3. Universal Wastes: These are commonly generated hazardous items that are subject to streamlined regulations. Examples include batteries, pesticides, mercury-containing equipment (e.g., bulbs), and some lamps.

4. Mixed Wastes: This category includes waste that contains both hazardous and radioactive components, making it subject to regulation by both the EPA and the Nuclear Regulatory Commission.

DIY kits are available for basic air quality testing, but professional services provide more comprehensive results and recommendations. While a DIY kit may seem cost-effective, a professional assessment is more thorough. Inspectors are better equipped to catch all pollutants and hazards, and you'll still need a professional to verify and act on DIY test results. Furthermore, some kits don't test for certain pollutants or only detect their presence without measuring specific levels (like mold spores). It's generally better to opt for a detailed professional assessment.

Lead removal is crucial in older homes to eliminate risks of lead poisoning, which can severely affect health, particularly in children, by impacting development and cognitive functions.

DIY lead testing kits are available, but they often lack the accuracy and reliability of professional services. Professional testing is recommended for more accurate results, as properly certified testers can provide a thorough analysis, clear recommendations, and the necessary legal documentation if remediation is required.