How come I keep having a lot of air pollution?

[Leogryph]

I put up plenty of parks, plenty of everything I can think of, and still there's a lot of air pullution. Do I need more parks? How many do I need so the pollution level isn't red?

[Smilies]

Parks and trees can only do so much. The best way to cut down on pollution is to offer more public transportation like busses and subways. You should enact ordinances like carpool and clean air act and automobile emission reduction. I think there might be a few other ordinances like recycling and landfill recovery that will help with air pollution. Planting mayor mode trees wherever possible can help a little bit as well.

[NAND]

Move your dirty industry and power plants to a neighbour city.

[sirgoodness]

First, the main points.
1. Dirty industry; it's synonymous with air pollution. The only way to deal with it to get rid of it.
2. If you use Coal, Oil, and/or Trash-to-Energy plants. They will need to go as well.
3. Heavy traffic in non-industrial areas. Ordinances and public transit will address this.

You should do what the others have said; enact the pollution-reducing ordinances, install public transit systems and move the power plants to another city. As for planting trees, there is a trick/cheat: you can open the pre-city god mode by opening god mode while holding down CTRL+ALT+SHIFT. Then you can plant trees for free at a ridiculously high rate. However, it is not a permanent solution to pollution.

With the power plants, you could also invest in clean energy (costly), isolate the polluting plants away from the rest of the city, and of course, use a cheat (fightthepower) to remove the need for power plants altogether :).

Keeping dirty industry out means taxing it out while balancing the demand for all other types of development, perhaps lowering taxes to attract manufacturing and/or high tech. Depending on the content of neighboring cities and the size of the one you're working on, this could be easy or difficult.

Those are all the options I know of to combat pollution in SC4. Hope this helps!