Air conditions/full house air circulation systems will clean the air to varying degrees, with the right filters. Filters are rated by FPR (Filter Performance Rating). A premium level (FPR 10 will trap small particles such pollen, mold spores, etc.) An PFR 4? Not so much.
Many Chihuahuas have skin reactions after playing outside in the yard, as they can be sensitive to
the grasses
(or the bugs, chemicals, and more that are found on those grasses). As the blades rub across the stomach, it causes a reaction. Once the Chihuahua puppy or dog comes back into the house, small red bumps may appear on the skin.
Since you want to be able to allow your Chi the fun and freedom of playing outside, wiping the belly skin down with baby wipes right after outdoor activity is done can help.
Food -
If a low quality food has been a Chihuahua's main food source, a change should be done to cut out fillers, artificial coloring, strong level of preservatives and other nasty elements that are found in inexpensive kibble.
A very small number of Chihuahuas will be allergic to very simple (and normally very healthy) ingredients. This even includes chicken. For this reason, if the vet suspects a
food allergy but is unable to narrow down the exact ingredient, owners can experiment at home to find the culprit.
You would want to begin by feeding the puppy or dog a very simple, home cooked recipe of chicken and one other ingredient. Many Chihuahua dogs love sweet potatoes. Another option is plain, white rice. There should be NO other added ingredients; no butter, no seasoning (except for a dash of salt).
Since it can take the body up to 3 weeks to shows signs of improvement AFTER a triggering food has been removed, keep the Chihuahua on this diet for 3 weeks. DO make sure to offer a full and complete vitamin and mineral supplement.
Once those first 3 weeks are complete, 1 ingredient can be added. This is often a healthy vegetable such as sweet baby peas or carrots. Again, no seasoning except a dash of salt, no butter or anything extra. This is fed for 3 weeks to see if there are improvements with the skin.
After this time, another ingredient is added and so on, until you have a nutritious full meal that can be fed from that time on. If you wish to eventually move back to a manufactured kibble, do be careful since additives, fillers, coloring and whatnot cannot be tested at home to see if there is a reaction.