Pollution Reduction
Pollution has wide-ranging negative effects on both human health and ecosystems. As we become more and more aware of the negative impacts that are being had, there is greater desire to develop ways to reduce the impact we are having. Regulatory practices, alternative energy sources, and conservation efforts are all being used in order to reduce the amount of pollution.
Reducing Air Pollution
Vapor Recovery Nozzles
These are found on pumps at gas stations and prevent VOCs from being released into the air while someone fills up their tank. Modern cars now have built-in onboard refueling vapor recovery systems (ORVR) which are more efficient than the nozzles at doing the same job.
Catalytic Converter
Required in ICE vehicles since 1975, these are components that convert air pollutants into other gases. Carbon monoxide, hydrocarbons, and nitrogen oxide are converted to carbon dioxide, oxygen gas, water vapor, and nitrogen gas.
Scrubbers
Commonly found on smokestacks of powerplants and factories, scrubbers work to remove particulates, sulfur oxides, and nitrogen oxides from industrial exhaust.
Wet scrubbers use a scrubbing liquid to catch the pollutants, while dry scrubbers typically use an alkaline material (such as lime or sodium bicarbonate) that reacts with acidic gases.
Fluidized Bed Combustion
Crushed coal is burned in a bed with limestone, which contains calcium carbonate, while jets of air are pumped in, increasing oxygen levels. The calcium carbonate reacts with sulfur dioxide, reducing its emissions. Calcium sulfate is formed, which is commonly used as sheetrock for home construction.
The increased oxygen content allows the coal to burn more efficiently, allowing it to burn at a cooler temperature. This reduces NOx emissions.
Electrostatic Precipitator
The exhaust gas is sent into a precipitator, where it passes a negatively charged plate, giving the particulates a negative charge. The charged particles are attracted to and stick to a positively charged plate, with the clean air being what is released.
The positively charged plates will be discharged and turned off every now and then, allowing the PM to fall off and be collected.
Baghouse Filter
Imagine if you took a brand new, white sock and put it on the exhaust pipe of your car. What would happen after a week (assuming it didn't fall off)? You could probably imagine that it would be really dirty looking.
Fabric filters can have gases pass through them, with the fabric then catching the particulate matter. There are often then shaker devices that work to shake and known down the trapped particulates so that the fabric (often a bag-like shape, hence the name) can be reused.
Laws and Regulations
It is in the best interest of governments to attempt to prevent and reduce air pollution in order to protect the health of their citizens and of the local environment. Environmental legislation has had significant impacts on reducing air pollution, as can be seen in the image to the left.
We have already discussed the Clean Air Act, and you are encouraged to reread that section, as it has been one of the most influential environmental laws in the US.
Another example of such legislation is CAFE, the Corporate Average Fuel Economy which sets minimum fuel efficiency (number of miles per gallon) standards for vehicles, with separate standards for "light-duty" (cars and light trucks) and "medium-duty" and "heavy-duty" vehicles.
Renewable Energy
The majority of air pollutants come from our reliance on and combustion of fossil fuels. By switching to renewable sources of energy (or clean but nonrenewable sources like nuclear), we can greatly reduce the amount of air pollution.
Waste Reduction
The Three Rs
Reduce: This involves using fewer things and minimizing the waste we produce. An example would be having everyone use reusable water bottles rather than each person using one-time-use plastic bottles. This is the most sustainable of the 3 Rs, as it decreases resource harvesting and energy use.
Reuse: This involves repeatedly using items, or parts of items, rather than just throwing them out after their primary use is done. For example, hand-me-down or thrifted clothes, or using old 2L pop bottles for a school project.
Recycle: This involves processing and turning waste into new products. This does not require new resource harvesting but is energy-intensive and can cost a lot of money. Unfortunately, most recycled materials are thrown away currently. In addition, many individuals "recycle" nonrecyclable materials, which increases the cost and effort to process and sort recyclables.
Composting
Organic matter, such as food scraps, grass clippings, and paper products don't need to be thrown out, they can naturally decompose. Not only does this reduce waste, but product of this decomposition is a great fertilizer and increases water holding capacity and nutrient levels of soil. By composting, methane release from landfills is reduced.
While many are hesitant to compost due to the perceived smell or the fear of attracating pests, there are methods to compost that minimize these drawbacks.